The present invention relates to the manufacture and charging with gas of gas cartridges, used, for example, for carbonizing water in siphons, for shooting from air weapons, for gas weapons, for inflating bicycle tyres.
Known in the art are technical solutions relevant to the structure of gas cartridges to be filled with a gas, for instance, with carbon dioxide gas CO2, such cartridges being provided with a cover which tightly closes the neck of the cartridge to preclude gas leakage.
As the cover, use is made of: a cap (U.S. Pat. No. 2,425,448, Cl. 220-3, 1947) placed onto the neck of the gas bulb and welded to the face portion thereof; a closure (U.S. Pat. No. 2,630,936, Cl. 220-3, 1953) with a cylindrical tubular skirt which is disposed inside the neck portion of the gas container, said closure having a horizontal annular flange welded to the face portion of the neck; a sealing plate (UK Patent Application GB No. 2,045,353, Cl. F16K 17/16, 1980) in the middle, in the upside and underside of which oppositely located recesses are provided, that facilitate piercing of the plate, a fold welded to the face portion of the neck of the gas cartridge consisting of one or two folding portions; two sealing plates (EP Patent No. 0,412,773, Cl. F17C 13/06, 1994), the first of said plates being expanded inside the neck of the gas cartridge and the second of said plates being welded from above to the neck; a sealing plate (U.S. Pat. No. 4,832,224, Cl. 220-89, 1989) with a regulator for quantity of flowing gas, when the pressure inside the gas cartridge sharply increases; a dome-shaped membrane (EP Patent No. 0,258,057, Cl. F17C 13/06, 1988) whose flange shoulders are expanded in the neck of the gas cartridge.
The prior art most relevant to the gas cartridge of the present invention is the structure of a pressure bulb disclosed in U.S. Pat. No. 2,685,383, Cl. 220-3, 1954, said pressure bulb having a body with a neck wherein the body of a cap is disposed, flanges of the cap being welded to the face of the neck.
The prior art most relevant to the method of charging the gas cartridge according to the present invention is the method disclosed in U.S. Pat. No. 2,685,383, Cl. 220-3, 1954,said method comprising introducing carbon dioxide gas in the form of xe2x80x9cdry icexe2x80x9d into the body of the pressure bulb, closing the bulb neck with a cap, pressing-in the cap, and welding the flange of said cap to the face of the neck.
All the above-cited devices and the method of charging suffer from the following common disadvantages. When charging is effected, e.g., with CO2, xe2x80x9cdry icexe2x80x9d, i.e., solid carbon dioxide is always used. xe2x80x9cDry icexe2x80x9d is produced from liquid carbon dioxide. Losses for converting carbon dioxide from the liquid to the solid state amount to about 30%. The operations of charging the gas cartridge or bulb, plugging the cartridge with a cap and welding the cap to the neck of the cartridge must be carried out in succession with a minimum interval of time therebetween for reducing gas leakage. The provision of such a technological process requires developing of complicated and costly equipment.
The idea central to the proposed technical solution is to provide a gas cartridge fitted with a structurally simple, easy to manufacture, convenient in service movable valve in the form of a spherical ball. Due to this feature the gas cartridge can be filled directly with CO2 in its liquid state, whereby the operation of preliminary CO2 conversion from the liquid state to the solid state of xe2x80x9cdry icexe2x80x9d is obviated, i.e. losses of carbon dioxide when filling the cartridge are reduced by at least 30%. The use of such a movable valve makes it possible to divide the process of manufacturing a filled gas cartridge into two independent technological operations spaced in time:
filling the cartridge with liquefied gas with the possibility of long-term storage thereof;
plugging the cartridge with a cap and welding the cap to the cartridge.
Thereby it becomes possible to simplify the requirements to the process equipment and, as a consequence, to cut down the manufacturing cost of gas cartridges.
This is accomplished due to the fact that the gas cartridge consisting of a body with a neck is provided with a cap which is inserted into the neck of the cartridge. Flanges of the cap are welded to the face of the cartridge neck, and the cap is provided with a membrane having a recess. Inside the body of the gas cartridge, prior to charging thereof with liquefied gas, a movable valve is arranged, this valve being a spherical ball whose diameter is larger than the diameter of the orifice in the neck. The length of the portion of the cap located in the neck is such that after installing the cap the ball cannot close the neck orifice completely.
In order that, after the membrane has been pierced, the ball could not shut off the ingress of gas from the gas cartridge into the cap, the end of the cap located in the neck is made with a chamfer or expanded, e.g., made xe2x80x9cstarxe2x80x9d-shaped.
The ratio of the averaged specific density of the materials from which the ball is manufactured and of the ball diameter is selected such that after charging the gas cartridges before closing the cartridge with the cap, the ball, under the effect of the gas pressure which is approximately 60 times the ambient pressure, could not jump out through the neck.
The ball can be manufactured from an elastic, resilient material; from an elastic, resilient material with a metallic powdered filler; be made fully metallic and enclosed in an elastic, resilient envelope.
In the proposed method of charging the gas cartridge, prior to charging it, a movable valve is placed into the body of the cartridge, then the cartridge is turned with its neck downward, and is charged with liquefied gas under a pressure, then the charging pressure is reduced, and the movable valve under the effect of the pressure inside the cartridge closes the orifice in the neck, so that the cartridge can be stored for a long time without the gas leakage therefrom; after that the neck is closed with the cap, the cap is pressed-in, and the flange of the cap is welded to the face of the neck.